DocuFest - the documentary wing of VideoFest - opens Thursday night in Dallas. To get you ready, we preview a pair of films that focus on the arts. "Dare to be Different" (Thursday at 9:15 p.m.) looks at an influential radio station that helped to popularize Depeche Mode, Blondie, Pet Shop Boys and other early '80s acts. And "Ex Libris: New York Public Library" (Saturday at 11 a.m.) is legendary documentarian Frederick Wiseman's look at one of the world's largest library systems.